Commit de81225a authored by Wim Van Sebroeck's avatar Wim Van Sebroeck
Browse files

[WATCHDOG] mpc5200_wdt clean-up 



* Add MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
* Add mandatory WDIOC_GETSTATUS and WDIOC_GETBOOTSTATUS ioctl's.
* If unknown ioctl is used we should return -ENOTTY.
* All watchdog device drivers are VFSs (Virtual File Systems).
  We thus return a nonseekable_open(inode, file) when we open the VFS.
* Make sure that /dev/watchdog can be opened by 1 parent
* Add spin-locking to prevent that forked children can disturb
  each other's operations.

Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 7d831bf5

drivers/char/watchdog/mpc5200_wdt.c

+30 −2
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#include <linux/miscdevice.h>

#include <linux/watchdog.h>

#include <linux/io.h>

#include <linux/spinlock.h>

#include <asm/of_platform.h>

#include <asm/uaccess.h>

#include <asm/mpc52xx.h>
@@ -19,8 +20,11 @@ struct mpc5200_wdt { 
	struct miscdevice miscdev;

	struct resource mem;

	struct mpc52xx_gpt __iomem *regs;

	spinlock_t io_lock;

};



/* is_active stores wether or not the /dev/watchdog device is opened */

static unsigned long is_active;



/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from

 * file operations, which sucks. But there can be max 1 watchdog anyway, so...
@@ -47,24 +51,31 @@ static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt) 
/* watchdog operations */

static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)

{

	spin_lock(&wdt->io_lock);

	/* disable */

	out_be32(&wdt->regs->mode, 0);

	/* set timeout, with maximum prescaler */

	out_be32(&wdt->regs->count, 0x0 | wdt->count);

	/* enable watchdog */

	out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT | GPT_MODE_MS_TIMER);

	spin_unlock(&wdt->io_lock);



	return 0;

}

static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)

{

	spin_lock(&wdt->io_lock);

	/* writing A5 to OCPW resets the watchdog */

	out_be32(&wdt->regs->mode, 0xA5000000 | (0xffffff & in_be32(&wdt->regs->mode)));

	spin_unlock(&wdt->io_lock);

	return 0;

}

static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)

{

	spin_lock(&wdt->io_lock);

	/* disable */

	out_be32(&wdt->regs->mode, 0);

	spin_unlock(&wdt->io_lock);

	return 0;

}
@@ -91,11 +102,17 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file, 


	switch (cmd) {

	case WDIOC_GETSUPPORT:

		ret = copy_to_user(data, &mpc5200_wdt_info, sizeof(mpc5200_wdt_info));

		ret = copy_to_user(data, &mpc5200_wdt_info,

			sizeof(mpc5200_wdt_info));

		if (ret)

			ret = -EFAULT;

		break;



	case WDIOC_GETSTATUS:

	case WDIOC_GETBOOTSTATUS:

		ret = put_user(0, data);

		break;



	case WDIOC_KEEPALIVE:

		mpc5200_wdt_ping(wdt);

		break;
@@ -112,15 +129,23 @@ static int mpc5200_wdt_ioctl(struct inode *inode, struct file *file, 
		timeout = mpc5200_wdt_get_timeout(wdt);

		ret = put_user(timeout, data);

		break;



	default:

		ret = -ENOTTY;

	}

	return ret;

}

static int mpc5200_wdt_open(struct inode *inode, struct file *file)

{

	/* /dev/watchdog can only be opened once */

	if (test_and_set_bit(0, &is_active))

		return -EBUSY;



	/* Set and activate the watchdog */

	mpc5200_wdt_set_timeout(wdt_global, 30);

	mpc5200_wdt_start(wdt_global);

	file->private_data = wdt_global;

	return 0;

	return nonseekable_open(inode, file);

}

static int mpc5200_wdt_release(struct inode *inode, struct file *file)

{
@@ -129,6 +154,7 @@ static int mpc5200_wdt_release(struct inode *inode, struct file *file) 
	mpc5200_wdt_stop(wdt);

	wdt->count = 0;		/* == disabled */

#endif

	clear_bit(0, &is_active);

	return 0;

}
@@ -173,6 +199,7 @@ static int mpc5200_wdt_probe(struct of_device *op, const struct of_device_id *ma 
	}



	dev_set_drvdata(&op->dev, wdt);

	spin_lock_init(&wdt->io_lock);



	wdt->miscdev = (struct miscdevice) {

		.minor	= WATCHDOG_MINOR,
@@ -256,3 +283,4 @@ module_exit(mpc5200_wdt_exit); 


MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");

MODULE_LICENSE("Dual BSD/GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);